Detecting a face region from a motion picture is one of the prerequisite steps in face recognition. Conventional schemes for detecting a face region have not been used widely, since those schemes are affected by background images, and the size and orientation of the face.
Detection of face regions may be performed by using the information of the shape, color, or motion of the faces.
Using shape information for detecting a face region may be performed by measuring variation of gray levels and app lying the measured values to a priori information of the face. However, the scheme should be applied only to images containing front side of a face, and the detection result is largely affected by background images, and the size and orientation of the face.
The scheme of using color information suffers from racial deviations of face colors, because the scheme detects a face region by using the inherent color of human faces. Further, the scheme requires large amount of data processing, since it uses much more information than the scheme of using shape information. However, it becomes more applicable than the scheme of using shape information, as hardware technology has recently developed.
The motion information may also be used for detecting face regions in motion pictures wherein an object, i.e. a face, is moving.